Sewing-machine



(No Model.)

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E. s, CRAM au E. o. GoVBLL.

SEWING MAGHINE.

Patented Apr. 14, 1885.

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UNITED STATES PATENT OFFICE.

ELISHA S. CRAM AND EDGAR C. OOVELL, OF LAOONIA, ASSXGNORS OF ONE- HALFTO JOHN S. CRANE AND B. FRANK DRAKE, OF LAKE VILLAGE,

NEW HAMPSHIRE.

SEWiNG-MACHINE.

SPECIFICATION forming part of Letters Patent No. 315,742, dated April14, 1885.

Application ilcal February 28, 1884i. (No model.)

To @ZZ whom, it may concern:

Be it known that we, ELisHa S. CRAM and EDGAR C. CovELL, of Laconia, inthe county of Belknap and State of New Hampshire, have invented anImprovement' in Sewing Machines; and we do hereby declare that thefollowing is a full. and exact description thereof, reference beinghadto the accompanying drawings, making part of this specification.

The purpose of our invention is to enable a sewing-machine to be runbackward without the shuttle being allowed to enter the needlethreadloop, which, if taken by the shuttle in the backward movement of themachine, will break the needlethread. Sewing-machines generally are soconstructed and organized that the shuttle takes the needle-thread loopwhen the machine is run backward.

By our present invention we effect the purpose by a peculiarconstruction of the, cani by which the needle-bar is driven with theeccentric or crank pin on the needle-driving shaft, substantially ashereinafter specied.

In the accompanying drawings, Fignrel represents a vertical sectionthrough the sewingniachine head and clotlrplate, looking out toward theshuttle and needle, the View showing our improvement; Fig. 2, a similarsection of the sewing-machine head in the same plane, but looking in theopposite direction to the View shown in Fig. l; Fig. 3, a face view oi'our improved needle-driving cani, it being shown in full lines, whilethe usual forni of the cam is indicated by dotted lines in the sameligure.

Like letters designate corresponding parts in all of the figures.

Let A represent the needle of a shuttle sewing-machine; B, theneedle-bar; C, the driving-cam on the needle-bar; D, the needledrivingshaft; E, the crank-pin or eccentric engaging with the cam on theneedle-bar, and G the shuttle.

All the parts of the sewing-machine are or may be constructed as usual,except the cam C on the needle-bar.

The groove of the cani C has two parts, c and b. The part ce, being theforward half, (with a machine organized as that shown in the drawings)is the part in which the crank-pin E asceuds and lifts the. needle-barto raise the needie when the machine is run forward in sewing; and thepart b, being the rear half, is the part in which the crank-pindescends. When the sewing-machine is run backward, however, thecrank-pin ascends in the rear part, Z1, and descends in the front part,c, and it is in this backward movement of the machine thatviews in Figs.l and 2 are taken. The forward part, c, of the cam-groove has a rapidupward turn, so that through the first quarter of a circle the crank-pinin ascending therein travels nearly in its own circular pathwaycoincident therewith, thus not lifting the needle, and thereby givingtime for the shuttle to pass through the needlethread loop, and theusual construction of the rear part, b, of the cam-groove is nearly ofthe same or corresponding shape, or with a similar abrupt rise outward,as indicated by dotted lines in Fig. 3, so that when the machine isturned backward the ascent of the needlebar is correspondingly retarded,thus delaying the raising of the needle till the shuttle enters theneedle-thread loop but the timing of the motions of the parts ai'iectedis such that the shuttle does not pass entirely through the saidthread-loop before the continually-ascending needle pulls np thethread-loop and causes the thread to be broken. Now, our improvedconstruction of the cam is such that in turning the machine backward theraising of the needie-bar and its needle is hastened sufficiently tocause the needlethread loop to be so far raised that the point of theshuttle when it reaches the needle, as shown in Fig. l, cannot enter thesaid needle-thread loop. We effect this by giving the rear part, b, ofthe camgroove substantially the form shown in Fig. 1, and by full linesin Fig. 3, it being much more depressed than with the usualconstruction, and, in fact, extending outward nearly at right angles tothe line of motion of the needle-bar. The forni of the groove may varysomewhat, and may be to any extent, provided that it quicken the ascentof the needle as and to the effect herein specified; and our inventionis intended to embrace any construction of cam or cam-groove which willeffect the result and fulfill the purpose herein set forth. In somesewing-machines the motions are reversed as to the forward and backmotions of the driving-shaft D, and the position of the parts of IOO ourimprov-ed cam-groove are alfeoted thereby, requiring in some machinesthe front, while in other machines the back of the groove has thespecial-form given by our invention.

We claim as our invention- 41. The combination, with thestitch-formingmechanismof a sewing-machine having a shuttle adapted to takethe loopsof the needle-v thread in the regular motion of the machine, of means,as the crank-pin E and the cam C, constructed With its reverse-motionneedleraising part b extended in a direction substantially at rightangles to the line'of the needles motion, whereby the needle is causedto carry its thread-loop up away from the shuttle when the motion of themachine is reversed.

2. In a shuttle-sewing machine, the needledriving `cam C, constructedwith its rear or reverse-motion needle-raising part b extended in adirection substantially at right angles to the line of the needlesmotion, in combination with the crank-pin E, needle-bar A, and shuttleG, whereby the needle is caused to carry its thread-loop up out of theWay of the shuttle when the motion of lthe machine is reversed. Y

The above speoication signed by us this 26th day of February, 1884i.

ELISHA S. CRAM. EDGAR C. COVELL. Vitnesses:

FRANK W. REEVES, EDGAR F. REEvEs.

